October has two birthstones: opal and tourmaline. Opal, the traditional stone, is famous for play-of-color, the rainbow flashes that move as the gem turns. Tourmaline, the modern addition, comes in more colors than almost any other gem, with pink the usual October choice. Opal is soft and needs care; tourmaline is the tougher of the two.
What is the birthstone for October?
Both stones are on the American list used by Jewelers of America and the American Gem Society. The Gemological Institute of America calls opal the traditional October birthstone and tourmaline the newer one.
Britain follows the same pattern: the National Association of Jewellers lists opal as the traditional gemstone and pink tourmaline as the alternative.
Any birthday can be looked up here. Type in the date to get the stones for that month, plus the flower and zodiac sign for the day.
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Opal and tourmaline at a glance
| Opal | Tourmaline | |
|---|---|---|
| Look | Flashes of many colors on a light, dark or orange body | Transparent, in almost any single color; some crystals show several |
| Mohs hardness | 5 to 6.5 | 7 to 7.5 |
| Everyday ring | Risky | Yes |
| Cleaning | Warm, soapy water only | Warm, soapy water and a soft brush |
| Main weakness | Heat, sudden temperature change, scratches | High heat |
Opal: the traditional October birthstone
Opal forms when water carries dissolved silica into cracks in rock and then evaporates. Precious opal is built of microscopic silica spheres stacked in a regular grid. Light bends as it passes between the spheres and splits into the colors of the spectrum, and the size of the spheres decides which colors you see. That effect is play-of-color.
The main types are named for their background:
- White or light opal: play-of-color on a pale body.
- Black opal: play-of-color on a dark body, the most dramatic look.
- Boulder opal: opal still attached to its host rock.
- Crystal opal: transparent to semitransparent, with a clear body.
- Fire opal: yellow, orange or red body, often with no play-of-color at all.
Australia is the most productive source: Lightning Ridge in New South Wales is famed for black opal, Coober Pedy in South Australia for white, and Queensland for boulder opal. Ethiopia and Mexico, the home of fire opal, are the other major sources.
Opal is sometimes impregnated with oil, wax or plastic, and thin slices are made into doublets and triplets. These are legitimate products at lower prices, but a seller should tell you which you are buying.
Tourmaline: the modern October birthstone
The name comes from the Sinhalese toramalli, "stone with mixed colors," and it fits. Tourmaline occurs in pink and red (called rubellite), emerald green, blue and violet, and a single crystal often holds more than one color. The neon blues and greens of "paraíba" tourmaline, colored by copper and first found in the Brazilian state of Paraíba in the late 1980s, are the most valuable.
For centuries tourmaline was mistaken for other gems. A Spanish conquistador in 1500s Brazil took green tourmaline for emerald, and "Caesar's Ruby" in the Russian crown jewels is really red tourmaline. It was recognized as a mineral of its own only in the 1800s.
Brazil is the leading source. Tourmaline is also mined in Afghanistan, Pakistan, Kenya, Madagascar and Mozambique, and in the United States in Maine and California.
What do the October birthstones mean?
Opal has gathered grand ideas. The Bedouin believed it held lightning and fell from the sky in thunderstorms. The ancient Greeks thought it gave the gift of prophecy. In Europe it long stood for purity, hope and truth, and because it shows every color it was said to hold the virtues of all gems at once.
Tourmaline's meanings depend on color: pink for love and compassion, green for courage and strength, black for protection.
Ancient writers also claimed opal guarded against disease. That is a belief from another age and not something any stone can do.
How to care for opal and tourmaline
Opal
- Clean it only with warm, soapy water.
- Keep it away from high heat and sudden changes of temperature, which can make it fracture.
- Don't soak doublets and triplets; water can weaken the glue.
- Store it apart from harder gems. Diamonds, rubies, sapphires and emeralds will all scratch it.
Tourmaline
- Clean it with warm, soapy water and a soft brush.
- Do not use ultrasonic or steam cleaners.
- It is stable in light and with most chemicals, but heat can damage it.
Gift ideas for an October birthday
- Opal earrings or a pendant let the colors show while protecting the stone.
- An opal ring works for occasions; choose a setting whose rim protects the edge of the stone.
- A pink tourmaline ring is the practical everyday choice.
- A bicolor tourmaline, pink at one end and green at the other, suits someone who likes the unusual.
- Price levels. Doublets, triplets and common tourmaline colors are affordable; fine black opal and paraíba tourmaline cost far more.
Opal marks the 14th wedding anniversary and tourmaline the 8th. Other years are in our guide to gifts for every wedding anniversary.
October birth flowers: marigold and cosmos
October's birth flowers are the marigold and cosmos. Marigolds, in orange and gold, carry meanings of warmth and joy in the traditional language of flowers, and also of remembrance. Cosmos, with its simple open petals in pink, white and crimson, stands for harmony, peace and love. Pink cosmos pairs well with pink tourmaline, and a pot of marigolds picks up the orange of a fire opal. The symbolism is old custom, nothing more binding than that. See every month's pair in our guide to birth flowers by month.
Earlier and later in the fall: sapphire for September and topaz and citrine for November. Every month sits side by side in birthstones by month.